A proposal has been made to add capacitors in order to achieve steep filter characteristics in a filter including resonators connected in a lattice pattern.
For example, as shown in FIG. 23, a proposal has been made for a circuit configuration of a surface acoustic wave (SAW) filter 1 including series-arm resonators 4 and 7 and parallel-arm resonators 8 and 9 connected in a lattice pattern between input terminals 2 and 5 and output terminals 3 and 6, and capacitors 10 and 11 connected in parallel to the parallel-arm resonators 8 and 9, respectively (for example, see Patent Document 1).
Patent Document 1: Japanese Patent No. 3389911